Physical Sciences and Mathematics Commons^™

Tertiary Structural And Functional Analyses Of A Viroid Rna Motif By Isostericity Matrix And Mutagenesis Reveal Its Essential Role In Replication, Neocles B. Leontis, Xuehua Zhong, Shuiming Qian, Asuka Itaya, Yijun Qi, Kathleen Boris-Lawrie, Biao Ding

Chemistry Faculty Publications

RNA-templated RNA replication is essential for viral or viroid infection, as well as for regulation of cellular gene expression. Specific RNA motifs likely regulate various aspects of this replication. Viroids of the Pospiviroidae family, as represented by the Potato spindle tuber viroid (PSTVd), replicate in the nucleus by utilizing DNA-dependent RNA polymerase II. We investigated the role of the loop E (sarcin/ricin) motif of the PSTVd genomic RNA in replication. A tertiary-structural model of this motif, inferred by comparative sequence analysis and comparison with nuclear magnetic resonance and X-ray crystal structures of loop E motifs in other RNAs, is presented …

Synthesis, Structure, Anion Binding, And Sensing By Calix[4] Pyrrole Isomers, Ryuhei Nishiyabu, Manuel A. Palacios, Wim Dehaen, Pavel Anzenbacher Jr.

Chemistry Faculty Publications

The synthesis, structure, and anion binding properties of chromogenic octamethylcalix[4] pyrroles (OMCPs) and their N-confused octamethylcalix[4] pyrrole isomers (NC-OMCPs) containing an inverted pyrrole ring connected via alpha'- and beta-positions are described. X-ray diffraction analyses proved the structures of two synthesized isomeric pairs of OMCPs and NC-OMCPs. The addition of anions to solutions of chromogenic OMCPs and NC-OMCPs resulted in different colors suggesting different anion-binding behaviors. The chromogenic NC-OMCPs showed significantly stronger anion-induced color changes compared to the corresponding chromogenic OMCP, and the absorption spectroscopy titrations indicated that chromogenic OMCPs and NC-OMCPs also possess different anion binding selectivity. Detailed NMR studies …

Molecular-Wire Behavior Of Oled Materials: Exciton Dynamics In Multichromophoric Alq(3)-Oligofluorene-Pt(Ii) Porphyrin Triads, Victor A. Montes, Cesar Perez-Bolıvar, Neeraj Agarwal, Joseph Shinar, Pavel Anzenbacher Jr.

Chemistry Faculty Publications

Donor-bridge-acceptor triads consisting of the Alq3 complex, oligofluorene bridge, and PtII tetraphenylporphyrin (PtTPP) were synthesized. The triads were designed to study the energy level/distance-dependence in energy transfer both in a solution and in solid state. The materials show effective singlet transfer from the Alq3-fluorene fluorophore to the porphyrin, while the triplet energy transfer, owing to the shorter delocalization of triplet excitons, appears to take place via a triplet energy cascade. Using femtosecond transient spectroscopy, the rate of the singlet−singlet energy transfer was determined. The exponential dependence of the donor−acceptor distance and the respective energy transfer rates of 7.1 × 1010 …

Mapped Overland Distance Of Paleotsunami High-Velocity Inundation N Back-Barrier Wetlands Of The Central Cascadia Margin, U.S.A, Robert B. Schlichting, Curt D. Peterson

Geology Faculty Publications and Presentations

Investigations of back-barrier, open-coastal plain settings have been used to establish minimum inundation distances of prehistoric tsunamis produced by great subduction zone earthquakes in the central Cascadia margin. Distinctive sand sheets were characterized at four localities within the central Cascadia margin, a shoreline distance of about 250 km. The sand sheets vary in thickness from 0.2 to 25 cm. They thin in the landward direction and consist of well-sorted beach sand that fines upsection. Many of the sand sheets include capping layers of organic-rich detritus, as well as assimilated mud rip-up clasts and soil litter. Marine diatoms and bromine (i.e., …

Practical Private Data Matching Deterrent To Spoofing Attacks, Yanjiang Yang, Robert H. Deng, Feng Bao

Research Collection School Of Computing and Information Systems

Private data matching between the data sets of two potentially distrusted parties has a wide range of applications. However, existing solutions have substantial weaknesses and do not meet the needs of many practical application scenarios. In particular, practical private data matching applications often require discouraging the matching parties from spoofing their private inputs. In this paper, we address this challenge by forcing the matching parties to "escrow" the data they use for matching to an auditorial agent, and in the "after-the-fact" period, they undertake the liability to attest the genuineness of the escrowed data.

Multi-Learner Based Recursive Supervised Training, Laxmi R. Iyer, Kiruthika Ramanathan, Sheng-Uei Guan

Research Collection School Of Computing and Information Systems

In this paper, we propose the multi-learner based recursive supervised training (MLRT) algorithm, which uses the existing framework of recursive task decomposition, by training the entire dataset, picking out the best learnt patterns, and then repeating the process with the remaining patterns. Instead of having a single learner to classify all datasets during each recursion, an appropriate learner is chosen from a set of three learners, based on the subset of data being trained, thereby avoiding the time overhead associated with the genetic algorithm learner utilized in previous approaches. In this way MLRT seeks to identify the inherent characteristics of …

Masking Page Reference Patterns In Encryption Databases On Untrusted Storage, Xi Ma, Hwee Hwa Pang, Kian-Lee Tan

Research Collection School Of Computing and Information Systems

To support ubiquitous computing, the underlying data have to be persistent and available anywhere-anytime. The data thus have to migrate from devices that are local to individual computers, to shared storage volumes that are accessible over open network. This potentially exposes the data to heightened security risks. In particular, the activity on a database exhibits regular page reference patterns that could help attackers learn logical links among physical pages and then launch additional attacks. We propose two countermeasures to mitigate the risk of attacks initiated through analyzing the shared storage server’s activity for those page patterns. The first countermeasure relocates …

Incorporating Support For Event Algebra In Relational Stream Systems, Vijay Dialani, Inderpal Narang

Vijay Dialani

Data stream management systems make prominent use of a subset of relational algebra for describing continuous queries. The phenomenon has highlighted the wide spread use of declarative interface for stream data manipulation. As relational algebra is set oriented while the data streams are essentially sequences of data, there exist some cases where the use of relational algebra to describe processing in a data stream management system is counter productive. Supporting event algebraic operations on stream systems represents one such case. We have developed a combination of sequence algebra and relational algebra that is capable of supporting event algebra. Our alternative …

Real-Time Measurements On Electron Plasma Response In Dielectrics Under Influence Of Ultrafast Laser Radiation, Sebastian Winkler, Jeremy Gulley, Igor Burakov, Razvan Stoian, Nadezhda Bulgakova, Anton Husakou, Alexandre Mermillod-Blondin, Arkadi Rosenfeld, David Ashkenasi, Ingolf Hertel, William Dennis

Jeremy R. Gulley

No abstract is currently available.

Ubiquitous Provision Of Context Aware Web Services, Irene Chen, Stephen Yang, Jia Zhang

Jia Zhang

No abstract provided.

The Localized Dynamics Of A Ca2+Channel (30-Minute Talk), Borbala Mazzag, Christoper Tignanelli, Gregory D. Smith

Borbala Mazzag

No abstract provided.

The Karst Of West-Central Florida, Lee J. Florea

Lee J Florea, PhD, P.G.

Caves, the cornerstone feature of karst aquifers, are little understood in Florida. This dissertation, which analyzes the morphology, elevation, lithologic setting, and hydrology of caves in west-central Florida, demonstrates that the karst of the unconfined Floridan aquifer differs from the paradigm view of karst presented in modern geology textbooks. The differences reflect setting: eogenetic (west-central Florida) vs. telogenetic (conventional).

Models Of Forbidden Line Emission Profiles From Axisymmetric Stellar Winds., R. Ignace, A. Brimeyer

Richard Ignace

A number of strong infrared forbidden lines have been observed in several evolved Wolf–Rayet (WR) star winds, and these are important for deriving metal abundances and testing stellar evolution models. In addition, because these optically thin lines form at large radius in the wind, their resolved profiles carry an imprint of the asymptotic structure of the wind flow. This work presents model forbidden line profile shapes formed in axisymmetric winds. It is well known that an optically thin emission line formed in a spherical wind expanding at constant velocity yields a flat-topped emission profile shape. Simulated forbidden lines are produced …

The Viability Of Is Enhanced Knowledge Sharing In Mission-Critical Command And Control Centers, Sameh A. Sabet

Dissertations

Engineering processes such as the maintenance of mission-critical infrastructures are highly unpredictable processes that are vital for everyday life, as well as for national security goals. These processes are categorized as Emergent Knowledge Processes (EKP), organizational processes that are characterized by a changing set of actors, distributed knowledge bases, and emergent knowledge sharing activities where the process itself has no predetermined structure. The research described here utilizes the telecommunications network fault diagnosis process as a specific example of an EKP. The field site chosen for this research is a global undersea telecommunication network where nodes are staffed by trained personnel …

Selected Problems Of Inference On Branching Processes And Poisson Shock Model, Satrajit Roychoudhury

Dissertations

This dissertation explores the development of statistical methodology for some problems of branching processes and poisson shock model.

Branching process methods have become extremely popular in recent days. This dissertation mainly explores two fundamental inference problems of Galton-Watson processes. The first problem is concerned with statistical inference regarding the nature of the process. Two methodologies have been developed to develop a statistical test for the null hypothesis that the process is supercritical versus an alternative hypothesis that the process is non-supercritical. Another problem we investigate involves the estimation of the 'age' of a Galton-Watson Process. Three different methods are discussed …

Feasibility Of Superconductivity In Semiconductor Superlatices, Kenneth P. Walsh

Dissertations

The objective of this thesis is to explore superconductivity in semiconductor superlattices of alternating hole and electron layers. The feasibility of superconductivity in semiconductor superlattices is based on a model formulated by Harshrnan and Mills. In this model, a semiconductor superlattice forms the layered electron and hole reservoirs of high transition temperature (high-Tc) superconductors.

A GaAs-A1xGa1-xAs semiconductor structure is proposed which is predicted to superconduct at Tc = 2.0 K and may be analogous to the layered electronic structure of high-Tc superconductors. Formation of an alternating sequence of electron- and hole-populated quantum wells (an electron-hole superlattice) in a modulation-doped GaAs- …

Detection Of Proteins By Two-Photon Excitation Of Native Fluorescence, Li Li

Theses and Dissertations

Proteins are of primary importance to the structure and function of all living cells. Study of proteins relies on the ability to separate a complex mixture so that individual proteins can be more easily processed by other techniques. Since protein samples often exist at low concentration in a small volume, the trend in chemical analysis is toward micro total analysis systems (µTAS) or lab-on-a-chip devices. Among µTAS separation methods, the relatively new electric field gradient focusing (EFGF) technique has shown potential. It focuses and separates analytes based on their electrophoretic migration in an opposing hydrodynamic flow. The detection principles that …

Fences And Deer-Damage Management: A Review Of Designs And Efficacy, Kurt C. Vercauteren, Michael J. Lavelle, Scott Hygnstrom

United States Department of Agriculture Wildlife Services: Staff Publications

White-tailed deer (Odocoileus virginianus) may cause more damage than any other species of wildlife. These damages include crop loss, automobile and aviation collisions, disease transmission, environmental degradation, and destruction of ornamental plantings. One practical method of controlling deer damage is the use of exclusionary fences. The relatively high cost of labor and materials required to build effective fences has limited most applications to the protection of orchards, vegetable farms, other high-value resources, and mitigation of human health and safety risks. Improvements in fence technology resulting in less expensive, yet effective fences have expanded the use of fences to manage damage …

Blackbird Use And Damage Of Wildlife Conservation Sunflower Plots: The Second Year, Jonathan M. Raetzman, George M. Linz, William J. Bleier

United States Department of Agriculture Wildlife Services: Staff Publications

Annual blackbird damage to sunflower is valued at $5 to $10 million. Perhaps more importantly, the National Sunflower Association has identified blackbirds as the key reason for growers to abandon sunflower in areas of prime production. North Dakota and South Dakota together produce approximately 70% of sunflower grown in the United States. This crop adds $906 million to the regional economy. To date, cost effective and environmentally safe methods to reduce bird damage to sunflower remain elusive. In the 1980’s, scientists from the National Wildlife Research Center (NWRC) showed that “decoy” sunflower plots can greatly reduce bird damage to local …

List Of Publications: Robert Powers

Robert Powers Publications

Chronological list of 57 published articles and chapters in chemistry. Current through August 2006.

Education In The Environment: A Hands-On Student Research And Outdoor Learning Experience: Quarterly Progress Report: Period Ending August 31, 2006, Margaret N. Rees

Reports (PLI Education)

During the past three months, the focus of the university’s efforts has included the following highlights:

• Forever Earth was scheduled for 13 days and benefited 110 individuals.
• The National Park Service piloted the concept of using Forever Earth as a mobile visitor center during busy summer weekends. During five outings, Park Service interpreters contacted 1,365 visitors.
• Forever Earth curricula for 5th, 6th, and 7th grades have been completed.
• A Preliminary Implementation Plan was created by the SNAP Conservation Education and Interpretation team.
• A report on the Clark County School District Teacher Survey: Attitudes, Perceptions, Barriers, and Desires for Field Trip …

Earthshine : Photometry, Modeling, And Spectral Observations, Jeffrey Patrick Hickey

Theses

The Earthshine group has been making sustained observations of the Earthshine from Big Bear Solar Observatory in California since late 1998. There have also been intermittent observations from 1994-5. High and low resolution Earthshine spectral observations have also been under taken at Palomar Observatory since 1999. The group has re-invigorated and modernized a nearly forgotten way of measuring the Earth's albedo, and hence its energy balance, previously studied by Danjon (and his followers) for about twenty-five years early in the last century, using their observations of the Earthshine from France. This is an overview paper covering observations, reductions, simulations, and …

Characterization Of Single-Sided Charge-Sharing Czt Strip Detectors For Gamma-Ray Astronomy, B Donmez, John R. Macri, James M. Ryan, Jason S. Legere, Mark L. Mcconnell, Mark Widholm, T Narita, L A. Hamel

Space Science Center

We report progress in the study of thick single-sided charge-sharing cadmium zinc telluride (CZT) strip detector modules designed to perform spectroscopy and 3-D imaging of gamma-rays. We report laboratory measurements including spectroscopy, efficiency and 3-D imaging capability of prototype detectors (15 × 15 × 7.5mm³) with 11×11 unit cells. We also report on Monte Carlo simulations (GEANT4 v7.1) to investigate the effect of multihits on detector performance in both spectroscopy and imaging. We compare simulation results with data obtained from laboratory measurements and discuss the implications for future strip detector designs.

Antarctic Temperatures Over The Past Two Centuries From Ice Cores, David P. Schneider, Eric J. Steig, Tas D. Van Ommen, Daniel A. Dixon, Paul Andrew Mayewski, Julie M. Jones, Cecilia M. Bitz

Earth Science Faculty Scholarship

We present a reconstruction of Antarctic mean surface temperatures over the past two centuries based on water stable isotope records from high-resolution, precisely dated ice cores. Both instrumental and reconstructed temperatures indicate large interannual to decadal scale variability, with the dominant pattern being anti-phase anomalies between the main Antarctic continent and the Antarctic Peninsula region. Comparative analysis of the instrumental Southern Hemisphere (SH) mean temperature record and the reconstruction suggests that at longer timescales, temperatures over the Antarctic continent vary in phase with the SH mean. Our reconstruction suggests that Antarctic temperatures have increased by about 0.2 degrees C since …

Structural Inference In Transition Measurement Error Models For Longitudinal Data, Wenqin Pan, Xihong Lin, Donglin Zeng

Harvard University Biostatistics Working Paper Series

No abstract provided.

Estimation In Semiparametric Transition Measurement Error Models For Longitudinal Data, Wenqin Pan, Donglin Zeng, Xihong Lin

Harvard University Biostatistics Working Paper Series

No abstract provided.

Nonparametric Regression Using Local Kernel Estimating Equations For Correlated Failure Time Data, Zhangsheng Yu, Xihong Lin

Harvard University Biostatistics Working Paper Series

No abstract provided.

Causal Inference In Hybrid Intervention Trials Involving Treatment Choice, Qi Long, Rod Little, Xihong Lin

Harvard University Biostatistics Working Paper Series

No abstract provided.

A Comparison Of Methods For Estimating The Causal Effect Of A Treatment In Randomized Clinical Trials Subject To Noncompliance, Rod Little, Qi Long, Xihong Lin

Harvard University Biostatistics Working Paper Series

No abstract provided.

Some Heuristics About Elliptic Curves, Mark Watkins

Mathematics - All Scholarship

We give some heuristics for counting elliptic curves with certain properties. In particular, we re-derive the Brumer-McGuinness heuristic for the number of curves with positive/negative discriminant up to X, which is an application of lattice-point counting. We then introduce heuristics (with refinements from random matrix theory) that allow us to predict how often we expect an elliptic curve E with even parity to have L(E,1)=0. We find that we expect there to be about c₁X^19/24(log X)^3/8 curves with |Delta|< X with even parity and positive (analytic) rank; since Brumer and McGuinness predict cX^5/6 total curves, this implies that asymptotically almost all even parity curves have rank 0. We …